Colchester Bantam Mk1 - Eccentric Spindle, damaged rear spindle bearing

I have Gamet on my spindle. No runout to identify.
I was curious, I went onto Gamet’s web site, they have several types.
Mine include a spring pre-load built into the bearing. No adjustment, ever.
As long as they are lubricated properly they are supposed to last decades of daily use.
Incredible.
Thanks for sharing.
Jeff
 
I dont know if anyone has ever done it by the book,but years ago we fitted a big dia set of Gamets to a machine,and included was a many page fitting instruction guide..........including such things as making a close fitting arbor,and reworking the bearing flange seating face to microns runout,installing the bearings in a clean room(joke where I worked),and a 12 hour running in period with temperature monitoring,and a complete redo if the temp rose above the chart at any time.
 
I dont know if anyone has ever done it by the book,but years ago we fitted a big dia set of Gamets to a machine,and included was a many page fitting instruction guide..........including such things as making a close fitting arbor,and reworking the bearing flange seating face to microns runout,installing the bearings in a clean room(joke where I worked),and a 12 hour running in period with temperature monitoring,and a complete redo if the temp rose above the chart at any time.

Pretty certain that I will never need or attain this level of precision ;) Though there probably are industries where this might be required, I think there is often a tendency for manufacturers to exaggerate requirements to justify expensive warranty, maintenance agreements and periodic calibration.
 
I am about to embark on fitting a new set of bearings to a Bantam. I would like the original poster to explain how he got the shaft out? Also what supplier did you use to get your bearings?

Thanks for leaving the details of the bearings for a future traveller.
 
Getting the spindle out is simple......however ,I suggest you remove the feed drive assy first ,to get it out of the way of the spindle gears.....which just slip off their splines ........Anyhoo,remove feed ,then remove rear spindle bearing nut........the rear bearing is a slip fit on the spindle,the front bearing slightly tighter,but nothing requiring a puller.............And ,in case it was missed......if you dismantle the rollers out of a Gamet bearing,and replace them out of order,there will be runout .....no ,I dont know why..........another point is the rear bearing ,being unflanged (plain) can be replaced by a shelf roller ......and this will have about 1/2 thou repeating runout every second revolution........Lathes fitted with off the shelf bearings as an economy measure will have a number of small runouts ,around 1/2 thou ........I have found this quite acceptable for hobby work.
 
Another comment...do not subject any component to freezing temperatures to ease assembly.........you will trap large quantities of water (condensation/frost) in these assemblies,and rust the bearings and shaft,and maybe jam the lot together with rust.......Lathes dont get hot enough to drive out condensation like engine parts do.
 
@john.k the spindle really doesn't want to come out. I think it must be seized on to the rear bearing. If that is the case I can't see a way forward.
 
Back
Top